JPS63266169A - Knocking control device for engine - Google Patents

Abstract

PURPOSE:To prevent worsening of follow-up of control of knocking, by a method wherein, in a device which controls a delay angle amount of an ignition timing during detection of the occurrence of knocking, a means which performs control so that with the increase in the number of revolutions of an engine, a control gain is increased is provided. CONSTITUTION:During running of an engine, a control unit 14 detects the intensity of knocking based on an output from a knock sensor 12, and based on a number of revolutions of engine signal detected by a crank angle sensor 20, the maximum allowable value of the delay angle amount of an ignition timing is calculated by using a map. Based on the intensity of knocking, an delay angle amount of an ignition timing is calculated to control an ignition coil 10. In this case, when the delay angle amount of the ignition timing exceeds the allowable value of the delay angle amount of the ignition timing, the ignition timing is delayed by allowable value to prevent the occurrence of a torque shock. An allowable value is set so that with the increase in the number of revolutions of an engine, the allowable value of the delay angle amount of the ignition timing is increased, a delay angle speed is increased, and follow-up of control of knocking is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a knocking control device that controls the amount of retardation of ignition timing in accordance with knocking intensity.

The knock detection level obtained by amplifying the average value of the output of the prior art knock sensor and adding an offset is compared with the output of the knock sensor, and if the knock sensor output exceeds the knock detection level, knocking is determined. , and the value obtained by integrating the voltage exceeding the knock judgment level is taken as the knocking intensity,
A non-king control device is known that controls a control amount such as engine ignition timing according to the knocking intensity so as to suppress knocking (for example, Japanese Patent Laid-Open No. 59-20
1977, etc.).

In this type of knock control device that suppresses knocking by retarding the engine's ignition timing according to the knocking intensity, torque fluctuations due to fluctuations in ignition timing are unavoidable while performing knocking control. . As long as the amount of retardation of the ignition timing is small, the body will hardly feel the torque shock caused by this torque fluctuation, but as the amount of retardation increases, the body will feel the torque shock, which will significantly affect driveability. inhibit. For this reason, in conventional knocking control devices, when the amount of retardation of ignition timing exceeds a predetermined value, measures are taken to reduce the retardation speed so that the body does not feel the torque shock. was.

Problems to be Solved by the Invention However, reducing the retardation speed when the amount of retardation of the ignition timing for suppressing knocking exceeds a predetermined value does not improve the followability of knocking control. As a result, knocking could not be sufficiently prevented in some cases.

OBJECTS OF THE INVENTION An object of the present invention is to provide an engine knock control device that can prevent the body from feeling torque shock without deteriorating the followability of knock control.

Structure of the Invention In order to achieve the above object, the present inventor has conducted intensive research and has discovered that as the engine speed increases, the body no longer feels torque shock even with the same amount of retardation. The higher the engine speed, the more
The above object is achieved by providing means for controlling the control gain to increase.

Example Hereinafter, an example of the present invention will be described based on the accompanying drawings.
Add detailed explanation.

FIG. 1 is an overall view of an engine including an engine knocking detection device according to an embodiment of the present invention, and FIG.
1 is a block diagram of a knocking detector of an engine knocking detection device according to an embodiment of the present invention. FIG.

In FIG. 1, an intake boat 4 right connected to an intake passage 3 and an exhaust boat 6 connected to an exhaust passage 5 are opened in a cylinder bore 2 equipped with a piston 1 that reciprocates up and down inside the cylinder bore 2, respectively. A fuel injection nozzle 7 is provided near the intake boat 4, and an air flow sensor 8 and a throttle valve 9 are provided upstream of the intake passage 3, respectively. Furthermore, an ignition plug 11 is provided at the top of the cylinder bore 2 so as to face into the cylinder bore 2, and the ignition coil 10 ignites the air-fuel mixture in the cylinder bore 2. A knock sensor 12 that detects vibrations is provided on the side of the cylinder bore 2. The outputs of the air flow sensor 8 and the knock sensor 12 are input to the control unit 13 along with a crank angle signal from a crank angle sensor (not shown) via the power distributor 13, and the control unit 13 uses the necessary input signals based on these input signals. performs various calculations and outputs various engine control signals. In the control unit 14, basic ignition timing control values are determined experimentally in advance according to the operating conditions and stored in the form of a map or the like.
Calculate the basic ignition timing control value according to the operating condition,
It is configured to output an ignition timing control signal to the ignition coil 10.

FIG. 3 is a block diagram of the inside of the control unit 14, and FIG. 2 is a block diagram of the knocking detector inside the control unit 14.

In FIG. 3, the signal is output from the output cover of the crank angle sensor 20 to the wave sweeper 21 of the control unit 14, and its waveform is shaped. The output of the crank angle sensor 20, whose waveform has been shaped, is sent to the computer unit 22 and the programmable counter 23, and is used to determine the timing of ignition timing calculation. A programmable counter 23 to which the output of the crank angle sensor 20 whose waveform has been shaped is input manually determines the energization time of the ignition coil 100 via an output interface 24. Also, for information storage, RAM (Random Access Memory) 25 and ROM (Read Only Memory)
26 are provided respectively. Knock sensor 12
The output is inputted to the knocking detector 27, the knocking intensity is detected by the counter 28, and a knocking intensity detection signal is inputted to the combinator unit 22. The output of the air flow sensor is analog buffer 2.
9 and the A/D converter 30, the fuel is inputted manually to the computer unit 23, where it is used to calculate the charging amount and corrected ignition timing.

FIGS. 3(1) and 3(2) are flowcharts showing a method of controlling the engine knocking control device according to the present embodiment. Figure 3 (1) shows the main routine in the third
Figure (2) shows the subroutines. In the control shown in the flowcharts of FIGS. 3 (1) and (2), the amount of retardation of the ignition timing that is allowable according to the engine speed is determined to increase as the engine speed increases, If the amount of retardation of the ignition timing calculated for the detected knocking intensity exceeds this tolerance value, the ignition timing is retarded by this tolerance value in one cycle to achieve the desired retardation. This delays the time it takes to quantify the amount. Here, the allowable amount of retardation of the ignition timing increases as the engine speed increases, so as the engine speed increases, the time for the ignition timing to be retarded to the desired amount of retardation becomes shorter. Therefore, the retardation speed is controlled to become faster. Therefore, it is possible to sufficiently prevent knocking without deteriorating the followability of knocking control.

The control shown in FIG. 3 (1) is performed every time the piston reaches top dead center. First, the flag K is set to zero, and the knocking intensity V detected by the knocking detector 27 is read. , based on the engine rotational speed detection signal detected by the crank angle sensor 20, the maximum allowable value S of the amount of retardation of the ignition timing is calculated. Here, the maximum allowable ignition timing retardation amount S with respect to the engine speed is determined in advance and stored in the computer unit in the form of a map or table. The allowable value S is calculated using this map or table. Next, the amount of retardation R of the ignition timing is calculated based on the read knocking intensity V. The calculation of the ignition timing retard amount R is also based on the knocking intensity V.
The desired ignition timing retard amount R is experimentally determined in advance and stored in the combination unit in the form of a map or table, and this map or table is used to perform the calculation. Next, it is determined whether or not the knocking intensity V is zero, that is, whether or not knocking is occurring.

When the knocking intensity V is zero and it is determined that no knocking has occurred, a basic ignition timing signal is output to the ignition coil 10, and ignition is performed. Figure 3 (1)
In , it is determined whether K is zero or not, but this is to distinguish it from the calculation when knocking occurs and the retard angle jlR with respect to the knocking intensity exceeds the allowable value S. Also, when it is determined that knocking has not occurred, the calculation 1 = Io +RL + R is performed, but since there is no knocking, R = 0.
Moreover, since RL=0 at the start of control, the ignition timing I becomes equal to the basic ignition timing I0.

On the other hand, when the knocking intensity V is not zero and it is determined that knocking has occurred, the subroutine shown in FIG. 3(2) is executed. That is, first, the flag It is determined whether

As a result, when it is determined that R is zero or negative, that is, the retard amount is equal to or smaller than the allowable value S, the process returns to the main routine and the arithmetic control is continued.

On the other hand, when it is determined that R is positive, that is, the amount of retardation exceeds the allowable value S, in order to limit the amount of retardation in that cycle to the allowable value S, X=X+1 is set, and the process is performed again. , R=R-5 is calculated, and it is determined whether R is zero or negative, that is, whether the remaining retard amount is not larger than the allowable value S even though the retard angle is retarded to the desired retard amount. It is determined whether

As a result, if it is still determined that R>0, then X=X
= 1, and this operation is repeated until R≦0.

On the other hand, when it is determined that R≦0, the remaining retard amount is
Since C is now below the allowable value S, even if the ignition timing is retarded based on that value, the problem of torque firing will not occur. Go back to your routine
Computation control continues. Here, Y corresponds to the quotient obtained by dividing the desired retardation amount calculated from the knocking intensity by the allowable value of the retardation amount at that engine speed, and 2 corresponds to the remainder.

Next, it is determined whether Y is zero.

As a result, Y=O1, that is, although knocking has occurred, if it is determined that the retardation amount R with respect to the knocking strength is less than the allowable value S, the basic ignition timing I is determined based on the retardation amount. is corrected according to the following equation, and the ignition timing signal I is output to the ignition coil 10, causing ignition.

1=ro +RL+R Here, RL is the previous retard amount, and after this, RL=R
Replaced with L+R and prepared for the next cycle.

On the other hand, when Y is not zero, that is, when knocking occurs and the retard angle IR for the knocking intensity exceeds the allowable value S, and it is recognized that it is necessary to reduce the retard speed, K=Y After replacing the value of K with Y, the ignition timing retard amount R for that cycle is set to the allowable value S, and the ignition timing I is calculated based on the following formula, and the ignition timing signal ■ is output to the ignition coil 10 to ignite.

After that, the next cycle starts and the knocking strength V
is read, the allowable value S of the ignition timing retardation amount is calculated based on the engine speed detection signal, and the ignition timing retardation ff1R is calculated based on the knocking intensity V.
It is determined whether or not is zero. Here, even if knocking occurred last time, the knocking has already been resolved in the next cycle, so even if knocking occurred last time and the desired retard amount R exceeds the allowable value S, The determination here is YES.

Therefore, next, it is determined whether the flag K is zero. The flag remains zero when knocking did not occur last time and when knocking occurred last time but the desired retard amount R for the knocking intensity was less than or equal to the allowable value S; , knocking occurred last time, and the ignition timing retard I with respect to the knocking intensity.
When R exceeds the allowable value S, K changes the previous desired retard amount R to the allowable @S at that engine speed.
It is the value Y of the quotient divided by Y, which is an integer greater than or equal to 1, so here we can determine whether knocking occurred last time and the amount of retardation R of the ignition timing relative to the knocking intensity exceeded the allowable value S. It will be determined whether or not.

When this judgment result is YES, that is, when knocking did not occur last time, or when knocking occurred last time, but the desired retard amount R for the knocking intensity was less than the allowable value S. , the ignition timing l is calculated according to the following equation.

1=゛Io +RL+R In this case, since knocking has not occurred,
The current retardation amount R is zero, but when knocking occurred last time, the ignition timing was retarded last time.
Since the previous retard angle ff1RL is not zero, the calculated ignition timing I is retarded from the basic ignition timing by the previous retard amount RL. That is, in this embodiment, when knocking occurs, the basic ignition timing itself is corrected.

On the other hand, when this determination result is NO, that is, when knocking occurred last time and the ignition timing retard amount R with respect to the knocking intensity exceeds the allowable value S, K=-1 is set, and , K is zero.

Here, the value of K at this point is the value obtained by subtracting 1 from the quotient Y of the previous desired retard angle iR divided by the allowable value S at that engine speed. When the retard angle 1iR is less than twice the allowable value S, the determination result is YES.

In this case, since the ignition timing has already been retarded by the ignition timing tolerance S last time, the retard amount R used to calculate the current ignition timing ■ is the previous desired retard amount R. It is sufficient to set it to the remainder Z when divided by the allowable value S at that engine speed, and with R=Z, the ignition timing ■ is calculated according to the following equation and output to the ignition coil 10.

I = Io + RL + R On the other hand, when the previous desired retard amount R is more than twice the allowable value S, K is still 1 or more, and the retard amount remaining until the desired retard amount is achieved. Since the amount still exceeds the allowable value S, the ignition timing ■ is calculated again according to the following formula by setting R=S and outputting it to the ignition coil 10. Then, the arithmetic control is further continued.

As described above, according to the present embodiment, when the amount of ignition timing retardation in relation to the knocking intensity exceeds the allowable value of the amount of ignition timing retardation determined according to the engine speed at that time, 1 In one cycle, the ignition timing is retarded by the allowable value to prevent torque shock, but as the engine speed increases, the allowable value of the ignition timing retard amount is set larger. As the engine speed increases, the retardation speed increases, making it possible to minimize the deterioration of followability of knock control.

The present invention is not limited to the above-mentioned examples, but various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. Needless to say.

For example, the flowcharts in the embodiments described above are merely examples, and control may be performed according to other flowcharts. - For example, in the above embodiment, when knocking occurs, it is assumed that there has been a change in the basic state of the engine, and the basic ignition timing itself is corrected, but the ignition timing is retarded due to one knock. Each time the control is completed, the previous retard amount may be set to zero so that the basic ignition timing is not corrected, and when the knocking intensity is zero, that is, knocking occurs. When knocking does not occur, the retard amount R is set to a negative value, and when knocking does not occur, the ignition timing is advanced to offset the retardation of the basic ignition timing due to knocking. You can also do this.

Further, the configuration inside the control unit 14 is not limited to the one described above, and various changes can be made.

Effects of the Invention According to the present invention, it is possible to provide a knocking control device that can prevent torque shock without impairing the followability of knocking control.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall view of an engine including an engine knocking control device according to an embodiment of the present invention, and FIG.
FIG. 1 is a block diagram of a control unit including an engine knocking control device according to an embodiment of the present invention. FIGS. 3(1) and 3(2) are flowcharts of an engine knocking control device according to an embodiment of the present invention. l...Piston, 2...Cylinder bore, 3...
・Intake passage, 4... Intake port, 5... Exhaust passage, 6... Exhaust boat, 7... Fuel injection nozzle, 8 Enerflow sensor, 9... Throttle valve, 10... - Ignition coil, 11... Spark plug, 12... Knock sensor, 13... Power distributor, 14... Control unit, 20... Crank angle sensor, 21... Wave sharper, 22... - Computer unit, 23... Programmable counter, 24... Output interface, 25...
R.A.M. 26...ROM. 27... Knocking detector, 28... Counter, 29... Analog buffer, 30... A/D converter.

Claims (1)

[Claims] An engine knocking control device for controlling the amount of retardation of ignition timing when the occurrence of knocking is detected, characterized in that the engine is provided with means for controlling the control gain so that the higher the engine speed is, the greater the control gain is. knocking control device.